This elegant and expensive appetizer is simply sieved and lightly salted fish roe (eggs). Sturgeon roe is premium and considered the "true" caviar. The three main types of caviar are beluga, osetra and sevruga. The best (and costliest) is from the beluga sturgeon that swim in the Caspian Sea, which is bordered by Russia and Iran. Caviar production is a major industry for both countries. Beluga caviar is prized for its soft, extremely large (pea-size) eggs. It can range in color from pale silver-gray to black. Next in quality is the medium-sized, gray to brownish gray osetra, and the smaller, gray sevruga caviar. The small, golden sterlet caviar is so rare that it was once reserved for Russian czars, Iranian shahs and Austrian emperors. Other popular (and much less expensive) types include lumpfish caviar (tiny, hard, black eggs), whitefish caviar (also called American Golden) with its small yellow-gold eggs and salmon or red caviar (medium-size, pale orange to deep red eggs). The word malossol on the label doesn't describe the type of caviar but rather the fact that the roe is preserved with a minimum amount of salt; malossol is Russian for "little salt. " Caviar is extremely perishable and must be refrigerated from the moment it's taken from the fish to the time it's consumed. Pasteurized caviar is roe that has been partially cooked, thereby giving the eggs a slightly different texture. It's less perishable and may not require refrigeration before opening. Pressed caviar is composed of damaged or fragile eggs and can be a combination of several different roes. It's specially treated, salted and pressed, and can in no way be compared to fresh caviar. Be sure to read the label for information on how to handle the caviar you purchase. Although only a spoonful of caviar supplies the adult daily requirement of vitamin B-12, it's also high in cholesterol and loaded with salt. Serve caviar very cold, preferably in a bowl that has been set into another container of ice. It should be presented simply, with toast points and lemon wedges. If desired, it may be garnished with sour cream, minced onion, and hard-cooked egg whites and yolks. Two classic caviar accompaniments are iced vodka and champagne.